So i sent an email and have not fount it anywhere else but i was wondering how it works with joining units.

an example i have is tau are battle brothers with space marines and space marines are battle brothers with inquisition but the tau are only allies of convenience with the tau.

How does it work with a unit of space marines joined with inquisition, can a tau character join the marines who they are battle brothers with even through they are only allies of convenience with the inquisition? does it work this way or what is the official ruling going to be?

There will be a FAQ update coming out soon, and this is what it says on the topic:

An Inquisitorial Independent Character may join a Battle Brother ally unit even if that unit has models attached from an army that would normally be an Ally of Convenience or a Desperate Ally of the Inquisition. In the case of a Desperate Ally the One Eye Open rule is ignored so long as one of the two models triggering the rule is attached to the Battle Brother Ally. Note that special abilities that apply to the unit will transfer to all models in the unit regardless of their ally affiliation.

o Ex 1: Inquisitor Coteaz may join a Space Marine Tactical Squad that also has a Tau Empire Commander attached to it. While in the same Space Marine unit, Coteaz and the Commander effectively ignore the One Eye Open rule. If an enemy unit triggers Coteaz’s I’ve Been Expecting You rule the Tau Commander will be able to fire with the unit.

o Ex 2: If an Ordo Xenos Inquisitor model joined to a Grey Knight Strike Squad is within 6” of an allied Necron Warrior unit the One Eye Open rule is effectively ignored.

Also FYI, no detachments in the army are allowed that are 'come the apocalypse' level on the ally matrix with each other, so no IG primary detachment with CSM allies with an inquisitorial detachment, for example (because the CSM & the Inquisitorial detachment are 'come the apocalypse').

GregSwanson wrote:On just a purely personal note I hate that ruling. Just opening things up for more abuse....

I hear you, but its GW's fault for making the game this way.

The reason this ruling needs to be made the way it is, is because when it comes to unit-based rules, if you suddenly say that a unit is no longer a certain type of unit because it gets joined by an allied IC, then you are left not knowing what that unit is in so many circumstances.

For example, an Eldar unit joined by a Dark Eldar character...if you try to say that this is no longer an 'Eldar' unit because it contains a DE model, then what type of unit is it? There isn't anything in the rules that would explain what these mixed units are, and that would create all kinds of new grey areas that would have to be covered via FAQ.

So even before this ruling, when it came to things like psychic powers being able to be used only on units from a specific type of codex, we have always stayed on the same path: even when joined by an IC from a different codex, the unit is still a unit from the original codex. So a Dire Avengers unit joined by a DE IC is still a Dire Avenger unit (just with a joined DE IC) and is therefore still a codex Eldar unit.

So to be consistent, we felt that we had to rule the same way on this issue.